Percutaneous Thermal Ablation for Small Renal Tumors: An Interview With Adam D. Talenfeld, MD

Adam D. Talenfeld, MD, is an attending physician at Weill Cornell Medical Center, New York Presbyterian Hospital in New York and a member of the Society of Interventional Radiology Foundation Quality and Outcomes Division’s Comparative Effectiveness Subcommittee. At the 2016 Annual Scientific Meeting of the Society of Interventional Radiology, he presented data about percutaneous thermal ablation (PA) vs surgery for small renal cancers. Here he shares some data and insights on the results.

IO360: Could you give a short overview of the design of the study?

Talenfeld: This is a population-based comparative effectiveness study of PA vs partial nephrectomy (PN) and radical nephrectomy (RN) for stage T1a renal cancers (<4 cm diameter). The SEER database, maintained by the National Cancer Institute, contains prospectively gathered data for 28% of all patients with cancer in the United States and is considered the highest quality cancer registry in the world. The SEER-Medicare database links SEER data with the 100% Medicare claims files, so we were able to analyze patient-specific information, including demographics, cancer histology and stage, medical comorbidities, treatments, and outcomes for a large groups of patients ages 65 and older. To minimize bias, we identified propensity score-matched cohorts of more than 850 patients each, separately comparing PA vs PN and PA vs RN.

IO360: What were some important findings from the study?

Talenfeld: We found that through 6 years of follow-up there were similar cancer-specific survival rates between patients who underwent percutaneous ablation vs patients who received either PN or RN. We also looked at cumulative complication rates at 30 and 365 days after treatment. In contrast to the similar survival rates, we found rates of complications after PA were much lower than after either type of surgery.

IO360: Was there anything surprising to you about the numbers of patients that you found in the group receiving radical nephrectomy vs partial vs PTA?

Talenfeld: Current American Urological Society guidelines, which date from about 2009, recommend surgery for all patients with small renal cancers and only recommend ablation as a consideration for patients who are poor surgical candidates. So I wasn’t surprised to find that a minority of patients were being treated with percutaneous ablation, but the markedly lower complication rates with PA was, I think, impressive.

IO360: So you would argue that ablation could be on an equal footing with radical nephrectomy for certain patients?

Talenfeld: It’s important to keep in mind that these are observational data, and that there are real-world biases baked into the data in terms of which patient gets which treatment. We found that patients who were referred for percutaneous ablation tended to be sicker and older than patients being treated with surgical options. When we adjusted for those differences, patients getting percutaneous ablation had half the rate of renal insufficiency at 1-year follow-up vs. patients getting radial nephrectomy. They also had half as many cardiovascular complications at 30 days compared to patients getting either surgery, and they had one-fifth as many other perioperative complications at 30 days, things like venous thromboembolic events, pneumonia, or ileus. This suggests that current guidelines may be in need of updating so that percutaneous ablation is offered sooner as an alternative to radical nephrectomy for older patients that have comorbidities. 

IO360:  Do you think that this would apply for just a certain subset of patients like an older group, or could this apply to a broader group?

Talenfeld: In order to best minimize bias, we looked at the subpopulation of T1a kidney cancer patients typically referred for percutaneous ablation. So one certainly needs to be careful about generalizing these findings to younger patients and to patients with few or no comorbidities. Clearly, there is room for more research into whether and to what extent PA might substitute for RN in the T1a population at large. But for older patients with comorbidities, our study supports greater use of this minimally invasive treatment over RN.

IO360: Is there anything you would like to add?

Talenfeld: I think it’s worth pointing out that randomized controlled trials are very costly to do in this patient population because renal cell is a more indolent cancer, so 5 years is considered midterm follow-up. So there is definitely a need for even longer follow-up, and, as you pointed out, there may be a role for conducting this kind of observational research in younger and healthier populations. Population-based comparative effectiveness research can be a uniquely powerful way of attempting to answer these health services questions that are important to patients, payers, and managing physicians.

Editor’s note: Dr. Talenfeld has completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. He reports that the work referred to in this interview was supported by the Association of University Radiologists GE Radiology Research Academic Fellowship (GERRAF), the Clinical and Translational Science Center at Weill Cornell Medical College (NIH grant UL1 TR000457) and a grant from the Society of Interventional Radiology Foundation.

Suggested citation: Ford J. Percutaneous thermal ablation for small renal tumors: an interview with Adam D. Talenfeld, MD. Intervent Oncol 360. 2016;4(9):E143-E145.